A large number of different driving wheels with pulleys are known. They are usually mounted at the front of an engine upon a protruding drive shaft. The driving wheels commonly cooperate with driving belts for driving further devices such as a dynamo. The driving wheels are subjected to rigid requirements. They are required to be reliable under different temperature conditions and be accurate as transferred motions must be synchronized with each other.
The driving wheels generally consist of a gear wheel with ledge-shaped, axially directed cogs and a sheet metal pulley screwed thereto. It is essential that no rotation of the pulley in relation to the gear wheel occurs. It is also important that the gear wheel fitted to a shaft not move in relation to the shaft. To achieve this lack of movement and rotation, there has been provided a central screw, which connects the driving wheel to the shaft, and a plurality of more peripherally situated screws, which connect the pulley to the gear wheel.
The driving wheels are commonly manufactured by means of powder metallurgy, and the material employed is a steel alloy. The wheels may also be forged.